I would recomnmend the following based on my experience
Use a program called GPSMapedit to create your map. We have used it to make our own GPS Routeable map of the entire Philippines
Buy a simple Garmin Nuvi GPS that save's tracks. Drive your entire site, stop and add POIS with details as you need
Upload the tracks into GpsMapedit as gpx files. You can overlay these on a Google Maps, Bing map if that helps as well
Trace your route and draw the roads, pois, etc in GPSMapedit
Export the work you have done as a shape file (You can actually load it as a map into your Garmin device for just your site, if you wanted to)
Set up Geoserver on a computer (can be windows or Linux) even your desktop Pc will do
Publish the Shape File in GeoServer
Style your layer as much as you like
Use OpenLayers as your Client interface to GeoServer.
Enjoy the efforts of your labor.
I just re-read your question and want to clarify that GpsMapedit will let you create whatever you want, Fire Hydrants, Pipes, Water Mains, Buildings, Walkways, Traffic Lights and so on. You can add them as either POI's, poly-lines, polygons and each of these can be styled in Geoserver SLD Styles to look just how you want them to.
What you are doing is not that unusual, perhaps the level of detail is a bit more than normally required, but Geoserver will handle the delivery and styling with ease.